Objective: To investigate the outcome of lateral femoral notch (LFN) after early anterior cruciate ligament (ACL) reconstruction and evaluate the recovery of knee joint function after the operation.
Methods: The clinical data of 32 patients who underwent early ACL reconstruction from December 2015 to December 2019 were retrospectively analyzed. The study included 18 males and 14 females, aged 16 to 54 years old, with an average age of (25.39±2.82) years. The body mass index (BMI) of the patients ranged from 20 to 30 kg/cm2, with an average of (26.15±3.09) kg/cm2. Among them, 6 cases were caused by traffic accidents, 19 by exercise, and 7 by the crush of heavy objects. MRI of all patients showed LFN depth was more than 1.5 mm after injury, and no intervention for LFN was performed during surgery. Preoperative and postoperative depth, area, and volume of LFN defects were observed by MRI data. International Cartilage Repair Society (ICRS) score, Lysholm score, Tegner activity levels, and knee injury and osteoarthritis outcome score (KOOS) were analyzed before and after the operation.
Results: All patients were followed up from 2 to 6 years with an average of (3.28±1.12) years. There was no significant difference in the defect depth of LFN from (2.31±0.67) mm before the operation to (2.53±0.50) mm at follow-up (P=0.136). The defect area of LFN was decreased from (207.55±81.01)mm2 to (171.36±52.69)mm2 (P=0.038), and the defect volume of LFN was decreased from (426.32±176.54) mm3 to (340.86±151.54)mm3 (P=0.042). The ICRS score increased from (1.51±0.34) to (2.92±0.33) (P<0.001), the Lysholm score increased from (35.37±10.54) to (94.46±8.45) (P<0.001), and the Tegner motor score increased from (3.45±0.94) to (7.56±1.28), which was significantly higher than that of the preoperative data (P<0.001). The KOOS score of the final follow-up was 90.42±16.35.
Conclusion: With the increase of recovery time after anterior cruciate ligament reconstruction, the defect area and volume of LFN decreased gradually, but the defect depth remained unchanged. The knee joint function of the patients significantly improved. The cartilage of the LFN defect improved, but the repair effect was not good.
Keywords: Anterior cruciate ligament reconstruction; Arthroscopy; Lateral femoral notch; Magnetic resonance imaging.